• The AWS Systems Manager CloudWatch Dashboard will no longer be available after April 30, 2026. Customers can continue to use Amazon CloudWatch console to view, create, and manage their Amazon CloudWatch dashboards, just as they do today. For more information, see [Amazon CloudWatch Dashboard documentation](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Dashboards.html). 

# How Patch Manager operations work
<a name="patch-manager-patching-operations"></a>

This section provides technical details that explain how Patch Manager, a tool in AWS Systems Manager, determines which patches to install and how it installs them on each supported operating system. For Linux operating systems, it also provides information about specifying a source repository, in a custom patch baseline, for patches other than the default configured on a managed node. This section also provides details about how patch baseline rules work on different distributions of the Linux operating system.

**Note**  
The information in the following topics applies no matter which method or type of configuration you are using for your patching operations:  
A patch policy configured in Quick Setup
A Host Management option configured in Quick Setup
A maintenance window to run a patch `Scan` or `Install` task
An on-demand **Patch now** operation

**Topics**
+ [How package release dates and update dates are calculated](patch-manager-release-dates.md)
+ [How security patches are selected](patch-manager-selecting-patches.md)
+ [How to specify an alternative patch source repository (Linux)](patch-manager-alternative-source-repository.md)
+ [How patches are installed](patch-manager-installing-patches.md)
+ [How patch baseline rules work on Linux-based systems](patch-manager-linux-rules.md)
+ [Patching operation differences between Linux and Windows Server](patch-manager-windows-and-linux-differences.md)